Corrosion inhibited lubricant composition



Unitedstates Patent" 6 hibited lubricant composition; More partieularly,- the in vention' is concerned with a nov l lubricating oil composition having improved corrosion inhibiting properties comparedto sin'lilarcompositions'of the p'riorfart. Lubricating oils" in general have a tendency to form decompositionprodu'cts due to oxidation. Many of these decomposition pr'oducts are" highly co'r'rosive to metals. Since lubricating oils duringnormal use come into contact with metal'surfaces, the problem 'of'controlling this corrosivity is one of majorimportance.

The decomposition and formation of corrosive prodnets in lubricating oils are promoted in particular by the increased temperatures, higher speeds and-reduced clearanceswhich are'commorily encountered in modern internal combustion engines today. Such engines also gener-' ally employ alloy metal bearings which arenotonly subject to corrosive attack, butalso exert a possible-catalytic.

effect on the decomposition of'the oil.

Present day lubricating oils for internal combustion engines are also commonly compoundedwith.agentssuch as detergents, sludge inhibitorsywear inhibitors and the like which are designed to loosen and suspend products of decomposition and counteract their effect.

products and also have an adverse effect on the I of the oxidation and corrosion inhibitors. Itthereforebecomes necessary to find inhibitors; which will function in combination withconventional detergents and sludge inhibitors in lubricating oil compositions. V

Oxidation and corrosion inhibitors which have been added to lubricating'o'ils heretofore to improve their resistance to decomposition and corrosivity usually contain. active sulfur in some form. Compositions containing. such inhibitors are generally. unsuitable forusewith silver bearings and the like 'whichare subject to attack by active sulfur. Although'a't onetime this would have'been only a minor problem, today the increasing use of silver alloy metal bearings in important classes of internal combustion engines such as marine and railroaddiesel engines emphasizes the need for corrosion inhibitors which do not depend on active sulfur-containing compounds for their eifectiveness.

Improved corrosion inhibited lubricating oil eompositions comprising lubricating oila nd a phthalic acid-have been prepared which have many advantages over pre'-' viously known lubricant compositions containing con ventional corrosion inhibitors. These compositions 'are described in Lowe and Stewart 478,517 and Stewart and Lowe application Serial No. 478,538, both of which werefiled'December 29,1954, both now abandoned; Other unusually elfective corrosion inhibited lubricant compositions: containing titanic acid complexes of glycols and-polyhdroxy benzenes'have also been described in Lowe application'Serial No. .440; 2 0, filed June 29, 1954. 1 r r l A superior new lubricant composition has now beenl:

Many of these agents add to the-corrosivity of the decomposition application Serial No.

. bymixingthe' phthalic acid and" titanic acid-complex'td- 2,809,132 Patented. Oct. 8, 1957 foundcomprising a major portion of an oil oflubricating' viscosity and a minor portion sufiicient. to inhibit cor rosion, of the reaction producttof a-phthalic acid-selected from the group consisting. of isophthalicacid= and tore phthalic acid reacted. with a titanic acidcomplex. of. a-

group. consisting of glycols andpoly hy- This new lubricant composition has enhanced anticorrosion properties which'are substantially superior to such properties of similar compositions emmember of the droxy benzenes.

ployed heretofore as discussed above.

The lubricant compositions-according to this invention containing thecombination of phthalic acidandtitanic acid complex of glycol or polyhydroxybenzene are surprisingly more effective in the inhibition of corrosion: than lubricant compositions containing either of theseadditives alone. Thisis all themore remarkable in view of the fact thatv lubricant compositions containing, the' phthalic acid and titanic acid complexes-of glycols and polyhydroxy benzeues individually have heretofore beeni considered outstanding corrosioninhibitors over which,

improvement would be exceedingly difficult.

The compositions of the. invention are further distin gui shed in that they may contain much larger' amounts of the very eifective phthalic acid corrosion inhibitor inf possible with lubricant compositions? stable form thanare containing it alone. Isophthalic acid and terephthali'c' acid} although excellent corrosion inhibitors, are in gen eral' very sparingly soluble in oilsof lubricating viscosity; and the incorporation of efliective amounts of such'inhibitorsin lubricant compositions presents a problem; Suspending agentssuch as lubricating oil detergent additives may be necessaryto maintain the phthalic acidsin stable form in the lubricant compositions. uctsofisophthalic acid and/or terephthalic: acid? with titanic acid complexes which are employed in the lubricant compositions. according tothis invention have greatly improved solubility characteristics compared to the phthal ic acids themselves. portions of the phthalic acid and titanic acidcoinplex ref action product corrosion give lubricant compositions capable of providing corrosion inhibition over extended periods ofoperation.

The improved lubricant compositions of the inventiondefinitely inhibit the tendency of oils to be corrosive to metal surfaces. When employed in the form ofinternal combustion engine lubricants which are normally corro'-" sive to alloy metal bearings, it is found that'the lubri cant compositions of the invention are substantially nonunder the more stringent" corrosive to the bearings, even operating conditions encountered in these internal combustion engines. i

The lubricant compositions have a further more particular advantage in that they are free of active sulfur. and are, therefore, ideally suited for use with important classes of internal combustion engines such as railroad and marine diesel engines which employ alloy bearings of silver and similar active sulfur.

The novel corrosion inhibited lubricating oil compositionsof the inventionare also" outstanding in that they may be compounded with additional agents such'as dc tergents, sludge inhibitors and wearinhibitors without' adversely aifecting theircorrosioninhibiting properties. The compositions also apparently act'as metaldeaetiva tors for the common bearing eating oils. 7 V

The reaction product of isophthalic acid and/or t'erephthalic acid with the titanic; acid complex is obtained The reaction prod Much larger and more effective proinhibitor may thus befr'eadily" incorporated without the need of suspending agents to metals that are subject to attackiby1 metals such as copper and lead which usually accelerate" the decomposition of'lubrigether. The reaction proceeds readily at room temperatuer (about 75 F.). However, heating the mixture to temperatures of from about 100 F. to about 300 F. is preferred to accelerate the reaction and insure completion.

The titanic acid complexes of glycols and polyhydroxy benzenes may be any of those described in Lowe application Serial No. 440,280. These compounds are characterized by a claw type of structure in which one or more rings of similar or unlike structure, due to the use of mixed glycols or polyhydroxy benzenes, are formed to include the titanium. Such compounds are commonly termed metal chelates in published literature. Although these compounds are referred to as titanic acid complexes for convenience, it is not necessary that they be formed by the reaction of titanic acid and glycol or polyhydroxy benzene. As a matter of actual practice, for present purposes, it is preferred to prepare the titanic acid complexes by mixing the more reactive titanic acid derivatives such as the titanium tetrahalides or titanium tetraalkyl esters with glycol or polyhydroxy benzene. The mixtures are ordinarily heated to accelerate the reaction.

As mentioned in the patent application of Lowe referred to above, the glycols which are reacted with the titanic acid derivative are preferably a and fl-alkane diols containing from 2 to 18 carbon atoms. these glycols include ethylene glycol, pentanediol-1,3,2- ethylhexanediol-1,3, 2,4,6-triethyldecanediol-1,3 and the like. The glycols of from 6 to 10 carbon atoms are preferred, since they import an optimum degree of oil solubility to the glycol titanate reaction product with isophthalic acid and/ or terephthalic acid and provide lubricant compositions which are unusually efiective in the inhibition of corrosion.

The polyhydroxy benzenes are most suitably the vicinal dihydric phenols such as catechol, tertiary butylcatechol and the like. Alkyl catechols containing from 2 to 18 carbon atoms in the alkyl groups are presently preferred, since they produce the most effective titanates in combination with phthalic acids.

The phthalic acid may be any of the phthalic acids referred to in the Lowe and Stewart application Serial No. 478,517 and Stewart and Lowe application Serial No. 478,538 already mentioned. For present purposes, terephthalic acid and isophthalic acid, particularly the latter, are preferred for the highly effective corrosion inhibiting lubricant compositions which are obtained when they are combined with titanic acid complexes in accordance with this invention.

The combination of phthalic acid and titanic acid complex of glycols and polyhydroxy benzenes is present in the lubricant compositions of the invention in amounts at least sufficient to inhibit corrosion. Small amounts, usually from about 0.01 to 10.0% by weight, based on the oil, are particularly suitable. Proportions ranging from about 0.5 to about 5.0% are preferred in most lubricating oil compositions to take advantage of enhanced solubility and provide the highest degree of effectiveness. Concentrates containing larger proportions, up to 50%, either in solution or suspension are useful in compounding operations. In this latter respect, the present invention finds particular utility, since increased amounts of phthalic acid may be incorporated due to their enhanced solubility in the form of the phthalic acid and titanic acid complex combinations.

The combination of phthalic acid with the titanic acid complex of glycols or polyhydroxy benzenes in the compositions of this invention includes a wide range of relative proportions of the phthalic acid and titanic acid complexes, since in any such combination the performance of either inhibitor will be enhanced by the addition of any amount of the other inhibitor. The more suitable ratios of titanic acid complex to phthalic acid, however, lie in the range of from about 0.5 to about moles of titanic acid complex to 1 mole of phthalic acid. Preferably, with the superior terephthalic acid and isophthalic acid com- Examples of binations referred to above, the ratios lie in the range of from about 2 to about 5 moles of titanic acid complex for each mole of phthalic acid.

Any of the well-known types of oils of lubricating viscosity are suitable base oils for the compositions of the invention. They include hydrocarbon or mineral lubricating oilsof naphthenic, parafiinic, and mixed naphthenic and parafiinic types. They may be refined by any of the conventional methods such as solvent refining and acid refining. Synthetic hydrocarbon oils of the alkylene poly mer type or those derived from coal and shale may also be employed. Alkylene oxide polymers and their deriva= tives such as the propylene oxide polymers and their ethers and esters in which the terminal hydroxyl groups have been modified are also suitable. Synthetic oils of the dicarboxylic acid ester type including dibutyl adipate, di- 2-ethylhexyl sebacate, di-n-hexyl fumarate polymer, dilauryl azelate, and the like may be used. Alkyl benzene types of synthetic oils such as tetradecyl benzene, etc., are also included. Liquid esters of acids of phosphorus in-' cluding tricresyl phosphate, diethyl esters of decane phos phonic acid, and the like may also be employed. Also suitable are the polysiloxane oils of the type of polyalkyl-, polyaryl-, polyalkoxyand polyaryloxy siloxanes such as polymethyl siloxane, polymethylphenyl siloxane and polymethoxyphenoxy siloxane and silicate ester oils such as tetraalkyland tetraaryl silicates of the tetra-2-ethylhexyl silicate and tetra-p-tert.-butylphenyl silicate types.

The corrosion inhibiting compositions of this invention are also outstanding in that they are unusually effective in the form of compounded lubricating oils containing conventional additives such as oxidation inhibitors, detergents or dispersants, sludge inhibitors, pour depressants, VI improvers, antifoaming agents, rust inhibitors, oiliness or film strengthening agents, wear inhibitors, dyes and the like. These compounded oils in normal use are generally corrosive to metal surfaces and alloy metal bearings in particular, and it is an exceptional attribute to the present compositions whereby corrosion inhibited compounded lubricating oils are provided. A further very desirable feature of the compositions according to the invention is the fact that the corrosion inhibition is obtained without any noticeable adverse effect on the other additives, thus permitting more efiicient all-around lubrication of internal combustion engines and other types of machines where unusually severe conditions of service are more and more commonly encountered.

A preferred embodiment of the present invention lies in the provision of a particularly eifective lubricant composition comprising a major portion of a mineral lubrieating oil in combination with an alkaline earth metal petroleum sulfonate and an alkaline earth metal alkyl phenate, said combination being corrosive to metal surfaces in normal use and a minor portion, sufficient to inhibit corrosion, of the reaction product of a phthalic acid selected from the group consisting of isophthalic acid and terephthalic acid with a titanic acid complex of glycols containing from 6 to 10 carbon atoms each. The sulfonates and phenates are present in any amounts sufficient to render the combination corrosive but most suitably in amounts of from about 0.1% to about 10% by weight of each, based on the compositions. Calcium and barium are illustrative of the alkaline earth metals. Such compositions are outstandingly efiective as lubricants for internal combustion engines.

The following examples are submitted as additional illustrations of the invention. These examples show the preparation of the reaction products of the invention and of the various lubricant compositions and the evaluation of their efiectiveness as corrosion inhibitors. The proportions given in these examples, unless otherwise specified, are on a weight basis and include both percent and millimoles per kilogram (mM./kg.) ,of the various additives.

EXAMPLE .1

i I This example. illustrates the .preparation of the. reaction product of isophthalic acid with glycol)titan-ate' in 1:2 molar ratio.

Into a one-liter, three-necked flask is charged 148.8 grams of 50% by Weight dihydroxy di(octylene glycol) titanate in cyclohexane solvent, 16.6 grams of isophthalic acid, 50 ml. ethanol and 100 ml. benzene. The flask is fitted with a thermometer, reflux condenser and stirrer. The mixture is heated to 120 F. at which point it becomes homogeneous. After stirring vigorously at reflux temperature for about two hours, the solvents are stripped off by distillation up to 350 F. at a pressure equal to about 2 mm. mercury. The reaction product obtained as. residue is a yellow, tacky solid material.

.4'grams of crude reaction product obtained above is dissolved in about 50 ml. of benzene at room temperature. 200 ml. of acetone is added to precipitate out a white, powdery material. 2.26 grams of the white, powdery material is thus recovered, amounting to a yield of 56.2% by weight based on the crude reaction product. This material has the following analysis:

Percent Ii=1 6. 9, 16.2 Percent :50.38, 51.33 Percent H=7.30, 7.01 Percent 0:24.42, 25.46

The white powder melts at a temperature of about 200 F.

EXAMPLE II dihydroxy di(octylene Material Benzene Isophthalic acid Insol. Butyl tri (octylene glycol) titanate Sol. Reaction product Sol.

From the above table it can be seen that the reaction product is soluble in hydrocarbons, whereas the isophthalic acid is insoluble.

EXAMPLE III This example illustrates the preparation of the reaction product of isophthalic acid with butyl tri(octylene glycol) titanate in 1:2 molar ratio and its incorporation into a lubricant composition.

Into a one-liter, three-necked flask equipped with thermometer, refluxcondenser, stirring means and addition funnel is charged 218 grams butyl tri(octylen e glycoD- titanate as a 60% solution in butanol, 19.5 grams isophthalic acid, 1.00 ml. isopropanol and 400 ml. benzene. The mixture is homogeneous at about 120 F. It is stirred vigorously at reflux temperature for about 2 hours. Following thisthe solvents, are stripped 01f by heating to 350 F. at a pressureof about 2 mm. mercury. The residue is a yellow, tacky naterialwhich is readily soluble in ethyl-' ether.

omb sl ce en i e i sqp i in 9f selv n e ned E he material is; combined witha compounded internal.

i tive in butyl alcohol), 4.98 grams of isophthalic acid, 20'

asqa ea 40 mineral lubricating oil-- base having a viscosity index of 60 and containing 10 mM./kg. of calcium petroleum sulfonate and'ZO mM./kg. of calcium alkyl phenate. This lubricant composition when tested in the copper-lead strip corrosion test and L-4 strip corrosion test, as described more particularly below, is found to be very elfective in the inhibition of corrosion.

EXAMPLE IV In this example the preparation of a lubricant composition containing the combination of isophthalic acid with butyl tri(octylene glycol)titanate is illustrated.

Into a two-liter, three-necked reaction flask is charged 43.5 grams of isophthalic acid by weight isophthalic acid and 15% by weight terephthalic acid). The flask is equipped with thermometer, reflux condenser, stirring means and addition funnel. 486.5 grams of butyl tri- (octylene glycol)titanate in butanol analyzing 60% active ingredient and 40% butanol is then added. 1008 grams of a solvent refined mineral lubricating oil and 250 ml. of ethyl ether are added. The mixture is stirred at reflux temperature, which is about F., for about two hours. The solvents (ethyl ether and butanol) are slowly dis tilled off under a reduced pressure equal to about 3 mm. mercury. The reaction flask is then heated to about 250 F. at the same pressure. 7

1340 grams of oil concentrate is produced by the above process. It contains butyl trioctylene glycol titanate and isophthalic acid combined in a mole ratio of about 2 to 1. It is perfectly clear in appearance at room temperature, indicating that the isophthalic acid is present in a completely stable form. 2.56% by weight of the product in lubricating oil yields a composition containing 10 mM./ kg. of titanium in the form of combined butyl trioctylene glycol titanic acid complex-and isophthalic acid.

Additional lubricating oil compositions containing different titanic acid complexes and phthalic acids in accord ance with the invention are prepared according to the procedure of the above example. Several illustrative'compositions of these types are further referred to in the examples which follow.

In comparison it is noted that the isophthalic acid and terephthalic acid are much less soluble in the lubricating oil compositions than the superior new reaction products of isophthalic acid or terephthalic acid with the titanic acid complexes. For practical purposes, the maximum isophthalic acid or terephthalic acid that can be incorporated into the lubricant compositions runs about 0.3%

by weight, whereas the reaction products of the phthalic the invention is also shown by their performance in the Copper-Lead Strip Corrosion Test. In this test a polished copper-lead strip is weighed and immersed in 300 ml. of test oil in a 400 ml. lipless Berzelius beaker. The test oil is maintained at 340 F. andstirred with a mechanical stirrer at 1000 R. P. M. After two hours a synthetic naphthenate catalyst is added to provide the catalytic metals commonly occurring in internal combustion engines. The test is continued 20 hours. The copper-lead strip is then removed, rubbed vigorously with a soft cloth and weighed to determine the net weight loss. V

The test oils include a representative compounded mineral lubricating oil of the internal combustion engine type which is normally corrosive to alloy metal bearings. In this case the compounded oil consists of a solvent refined SAE 40 mineral lubricating oil base having a viscosity index of 60 and containing 10 mM./kg. of calcium pe- Table l COPPER-LEAD STRIP CORROSION TEST Copper-Lead Additive Strip Weight Loss (mg) Nonecompounded oil alone 253. 1 0.6% Butyl tri(octylene glycol)titanate in compounded 011 14.0 0.6% Tetra(octylene glycobtitanate in compounded oil 27. 1 0.5% Butyl tri(octylene glycl)titanate and isophth acid in compounded oil (Example III) 6. 1 0.75% Butyl tri(octylene glycol) titanate and isophthalic acid in compounded oil (Example 111) 7. 1.0% Butyl tri(octylene glycODtitanate and isophthalic acid in compounded oil (Example III 7.1 1.0% Butyl tri(octylene glycol)titanate and isophthahc acid (2 to 1 mole ratio) in compounded oil 7.1 1.0% Butyl tri(octylene glycoDtitanate and tcrephthalic acid (2 to 1 mole ratio) in compoundcdoil 7. 7 1.0% Tetra(octyleno glycQDtitanate and isophthalic acid (2 to 1 mole ratio) in compounded oil 4. 4 1.0% Tetra(alkylene glycol)titanate and terephthalic acid (2 to 1 mole ratio) in compounded o1l.. 8. 4 0.5% Butyl tri(octylene glycol)titanate and isoplithalic acid (2 to 1 mole ratio) in compounded oil 7. 6 0.3% isophthalic acid torephtha-lic acid) in compounded oil 13.8

The above test data show that typically compounded mineral lubricating oils for internal combustion engines will give copper-lead strip weight losses in excess of 250 mg. On the other hand, compositions containing the same compounded mineral lubricating oil in combination with phthalic acid and titanic acid complexes in accordance with the present invention give remarkably low weight losses of as little as 4.4 mg. Such results are surprising, since they are substantially lower than the weight losses occurring when either phthalic acid or titanic complex is employed alone, even though these particular corrosion inhibitors have been considered particularly outstanding heretofore. In comparison with the remarkably eifective new lubricant compositions of the invention, the test results show that about 200% more corrosion is obtained in lubricant compositions which employ the maximum practical amounts of isophthalic acid and terephthalic acid of about 0.3%.

In another test which is a modified version of the copper-lead strip corrosion test described above, the effectiveness of the corrosion inhibited lubricant compositions according to this invention in respect to rubbing surfaces is demonstrated. In this test, which is commonly termed the interrupted copper-lead strip corrosion test, the same procedure is followed as in the copper-lead strip corrosion test, except that the test is interrupted at fourhour intervals to insert a new copper-lead strip. The test results are then given in the cumulative weight loss of all the strips. By changing the strips during the test, a fresh, clean metal surface is periodically exposed to the corrosion inhibited composition. Thus, the wiping effect obtained in rubbing metal surfaces such as bearings is simulated, and it is shown what happens when any protective film laid down on the metal surface during operation is removed.

The test results reproduced in the above table demonstrate the effectiveness of lubricant compositions according to the invention under conditions where any protective coatings formed by the corrosion inhibitors on the 8 metal surfaces are removed, as they would be by rubbing action in the case of bearings during actual operation of internal combustion engines. The results show that the compositions containing combined phthalic acid and titanic acid complexes are surprisingly superior to compositions containing titanic acid complex alone.

The lubricating oil compositions illustrative of the invention are also evaluated for their effectiveness as inhibitors in gasoline-type internal combustion engines. This test is termed the L-4 strip corrosion test because of its correlation with the L-4 Chevrolet engine test referred to in the CRC Handbook, 1946 edition, Co-ordinating Research Council, New York, New York. In the test the same apparatus and conditions as described in the above Copper-Lead Strip Corrosion Test are employed with two essential modifications. The temperature is maintained at 295 F. to simulate lower temperatures encountered in gasoline engines, and a synthetic naphthenate catalyst is used containing lead in further duplication of gasoline engine operation. The reference oils are conventional compounded mineral lubricating oils of the types described in the above tests. The results of the test are as follows:

Table III L-d STRIP CORROSION TEST Copper-Lead Additive Strip Weight Loss (mg) None-componnded oil alone 250.0 0.1% Terephthalic acid in compounded oil 45. 8 0.6% Butyl tri(octylene glycol) titanate in compounded oil. 13. 0 0.5% Bntyl tri(octylene glycoDtitanate and isophthalic acid in compounded oil (Example III) 18.8 0.75% Butyl tri(octylene glycoDtitanate and isophthalic acid in compounded oil (Example III) 9. 2

1.0% Butyl tri(octylene glycoDtitanate and isophthalic acid in compounded oil (Example III 4.1 1.0% Butyl tri(octylene glycol)titanate and isophthalic acid to 1 mole ratio) in compounded oil 4.1 1.0% Butyl tri(octylcne glycoDtitanate and terephthalic acid (3 to 1 mole ratio) in compounded oil 3. 7

The illustrative test results tabulated above show that the lubricant compositions according to this invention are unusually effective under low temperature operating conditions such as those encountered in gasoline internal combustion engines. Although the corrosivity of compounded lubricating oils generally employed in this type of engine ordinarily runs as high as 250 mg. copper-lead strip weight loss, the compositions of the invention containing the combination of phthalic acid and titanic acid complex give strip corrosion losses of as little as 3.7 mg.

In the above examples the octylene glycol was illustrative of the ,B-alkanediols, namely 2-ethylhexanediol-l,3. The alkyl phenate was cetyl phenate, representative of the well known alkyl phenate lubricating oil additives.

The nature of the improved lubricating oil compositions of the invention and their effectiveness should be readily apparent from the many illustrations given above. Corrosivity in the compositions is definitely inhibited to a very substantial degree. Particularly corrodible metals such as engine alloy bearings of copper, lead, and the like, as well as bearings of silver, are not adversely affected. This is indeed remarkable, since the problem of devising lubricant compositions uniformly noncorrosive to both tfipes of bearing metals has long confronted workers in t e art.

Due to the enhanced solubility of the reaction products of isophthalic acid and/or terephthalic acid with the titanic acid complexes, substantial amounts of the corrosion inhibitor, of 0.5% by weight and more, may be employed in the lubricant compositions according to the inventions. Improvements are thus obtained over similar lubricant compositions containing either the phthalic acid or the titanic acid complexes alone. As shown by the actual tests set out above, the advantages of these improvements are obtained in many different types of engine service desirable properties of the lubricant tion, sufficient to inhibit corrosion of the reaction prod- 7 not of 1 mole of a phthalic acid selected from the group consisting of isophthalic acid and terephthalic acid with from about 0.5 to 5 moles of a glycol titanate selected from the group consisting of triglycol and tetraglycol titanates, said glycols containing from 6 to 10 carbon atoms each.

2.v A lubricant composition comprising a major portion of a mineral lubricating oil in combination with an alkaline earth metal petroleum sulfonate and an alkaline earth metal. alkyl phenate said combination being corrosive to metal surfaces in normal use and from about 0.01 to 5.0% by weight of the reaction product of 1 mole of a phthalic acid selected from the group consisting of isophthalic acid and terephthalic acid with from about 0.5 to 5 moles of a glycol titanate selected from the group consisting of triglycol and tetraglycol titanates, said glycols containingfrom 6 to 10 carbon atoms each.

3. A'lubricant composition comprising a major portion of a mineral lubricating oil in combination with a calcium petroleum sulfonate and a calcium alkyl phenate said combination being corrosive to metal surfaces-in normal use and from about 0.01 to 5.0% by weight of the reaction product of 1 mole of a phthalic acid selected from the group consisting of isophthalic acid and terephthalic acid with from about 0.5 to 5 moles of a glycol titanate selected from the group consisting of triglycol and tetraglycol titanates, said glycols containing from 6 to 10 carbon atoms each.

4. A lubricant composition a major portion of a mineral lubricating oil in combination with a calcium petroleum sulfonate and a calcium alkyl phenate said combination being corrosive to metal surfacesin normal use and from about 0.01 to 5.0% by weight of the reaction product of 1 mole of a phthalic acid selected from the group consisting of isophthalie acid and terephthalic acid with 2 moles of a glycol titanate selected from the group consisting of triglycol and tetraglycol titanates, said glycols containing from 6 to 10 carbon atoms each.

5. A lubricant composition comprising a major portion of a mineral lubricating oil in combination with from about 0.1 to 10% of an alkaline earth metal petroleum sulfonate and from about 0.1 to 10% of an alkaline earth metal alkyl phenate said combination being corrosive to metal surfaces in normal use and from about 0.01 to5.0% by weight of the reaction product of 1 mole of a phthalic acid selected from the group consisting of isophthalic acid and terephthalic acid with 2 moles of a glycol titanate selected from the group consisting of triglycol and tetraglycol titanates, said glycols containing from 6 to 10 carbon atoms each.

6. A composition comprising a major portion of a mineral lubricating oil in combination with from about 0.1 to 10% by weight of a calcium petroleum sulfonate and from about 0.1 to 10% by weight of a calcium alkyl phenate, said combination being corrosive to metal surfaces in normal use and from about 0.01 to 5% by weight of the reaction product of 1 mole of isophthalic acid heated with 2 moles of butyl tri(octylene glycol)titanate at a temperature of from about F. to about 300 F.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A LUBRICANT COMPOSITION COMPRISING A MAJOR PORTION OF A MINERAL LUBRICATING OIL IN COMBINATION WITH AN ALKALINE EARTH METAL PETROLEUM SULFONATE AND AN ALKALINE EARTH METAL ALKYL PHENATE, SAID COMBINATION BEING CORROSIVE TO METAL SURFACES IN NORMAL USE AND A MINOR PORTION, SUFFICIENT TO INHIBIT CORROSION OF THE REACTION PRODUCT OF 1 MOLE OF A PHTHALIC ACID SELECTED FROM THE GROUP CONSISTING OF ISOPHTHALIC ACID AND TEREPHTHALIC ACID WITH FROM ABOUT 0.5 TO 5 MOLES OF A GLYCOL TITANATE SELECTED FROM THE GROUP CONSISTING OF TRIGLYCOL AND TETRAGLYCOL TITANATES, SAID GLYCOLS CONTAINING FROM 6 TO 10 CARBON ATOMS EACH. 